Before the great boneyards of the American West began pouring forth their treasures in 1877, the eccentric, brilliant paleontologist Edward D. Cope was so excited to have found a new skeleton at the bottom of a New Jersey marl pit that he bought a home in nearby Haddonfield to be closer to the fossil source. Cope named the new creature Laelaps and reconstructed it in the upright fashion of Joseph's Leidy's kangaroo-like Hadrosaurus, contrary to Richard Owen's quadrupedal poses. Finding Hadrosaurus a nemesis in Laelaps wasn't just happy coincidence; it was demanded by the hottest new natural law to hit 19th-century science since the conservation of energy.

"Nature red in tooth and claw" began as Charles Darwin's explanation of evolution by natural selection, but it became the mantra of an entire age. Victorians led by the philosopher Herbert Spencer invoked the "survival of the fittest" to justify everything from ruthless capitalist competition to inequalities between social classes. Prehistoric times made an ideal morality play about the struggle for survival, casting exotic actors in familiar roles. Fierce predators, revered for their combat skill, weeded out the unworthy among the blameless, prolific herbivores.

In this script for the drama of life, catching a meal or avoiding becoming a meal were seen as the chief preoccupation of all animals. Social behavior, including finding a mate or raising young, was seldom studied in living animals, much less deduced from the fragmentary traces left by the long-dead dinosaurs.